Improvement in dividers and calipers



' G. W. LANE.

. Dividers.

No. 108,799. Pate'ntedNov. 1, 1870.

1); W @-QW,, 6% z tttiuh'fiiater 35mm dffim GEORGE w. LANE, OF'PLANTSVILLE, ooNNEorIo T, ASSIGNOR OAEL'ISHA R. NEWELL, or SAME P AoE.

Letters Patent No. 108,799, dated November 1, 1870.

v IMPROVEMENT IN DI VI DERS AND CALIPERS.

The Schedule referred to in these Letters Patent and making p art' of the same.

I,'GEORGE W. LANE, of Plantsville, in the county of Hartford and State of Connecticut, have invented a new and useful Improvement in Dividers andOali-' pers, of which the following is a specification.

My invention'consists in theeinplo'ym'ent of a slotted ringor diskarranged around thejoint of an ordinary divider or caliper, and sunk into recesses in the sides of tlie'legs' of said instrument, and of the pe-, culiar arrangement of firmly setting the spring leg of circular slot, to, and a similar but shorter slot, 1).

A stud or arm, 0, is formed on or riveted to the disk A, in which stud is a set-screw, B.-

The disk A has a 'circularvopening in its center suffieiently large to admit the whole joint of the dividers, thus forming the disk A into a flat-slotted ring, which is sunk into the divider-legs O 0' near the joint d, in such manner that the joint (I is in the center of the disk A. 1 V

' A thumb-screw, j, passes through the slot-d into the leg 0'.

A bolt, h, passes through the slot b and leg 0, and is provided with a thumb-nut,

The usual spring 7; is secured to the leg 0, while a pin, m, orany proper projection, is secured to the disk A in such manner as to'come in contact with and confine the spring 71.

For an ordinary adjustment of the dividers the thumb-screw f is loosened, which will allow the legs 0 O to open or close to the, desired point, when they are secured by tightening the screw fl For a more particnlaror finer adjustment thelegs are set at nearlythe' desired point. bythe thumb: screw f, when the thumb-nut t is loosened, and'by turning the screw 13 against the leg 0,.the bolt 7 'being free to move in the short slot 7), the spring k is compressed until the legs 0 0 are adjusted to the desired point, when the thumb-nut t is again tight-1 ener], which firmly secures both legs 0 O in their placebeyond any probability of displacement by use.

In ordinary dividers and calipers, which are adjusted by a spring, no arrangement is made for securiugthe spring lcg'aside from the rigidity of the spring, and which is liable to yield, thus varying the distances in spacing or making irregular lines in describing a circle on a rough surface. By my invention the above objection isventirely overcome. The disk, being circular, gives superior strength to the device, and prevents the legs from twisting, as is often the-case when the usual curved arm is used. Thedisk being. arrangedatthe end around the joint presents a very convenient handle for operating the instrument, and thus removes the liability of compressin'gthe legs by griping their-41p 7 per ends for use.

I do not claim the circular slot and set=scrcw for adjusting divider or' caliper-legs; neither do I claim a sheet-metal divider or caliper-leg with a circular disk formed on its joint en'c. e

I claim as my invention The combination of the disk A, slots ('6 b, thumb or set-screws f and B, bolt h, thumb-nut t, spring k, pin

an, and divider or caliper-legs G 0, all substantially asdcscribed, whereby the spring leg, when adjusted, may be firmly fixed in place.

GEORGE LANE.

Witnesses:

' SIMEON H, N onrron,

JOSEPH K. SHEPARD. 

